A Raven, a Goth, a Gadget (or a few), a Ghost...it must be...

Ghosts and Gadgets
MARCUS SEDGWICK

Readers of Class War will get indignant when they read this book, because it is always the servants who die.  Everyone else will be too busy chuckling at the antics of Edgar the Raven, Guardian of Castle Otherhand and the Otherhand Family itself.

In the second of the Raven mysteries, Edgar is pitted against a guh...guh...You Know What that is frightening people to death (see above.)  It is not really as funny as the first Mystery, Flood and Fang, simply because the joke is now familiar, but it is still an amusing diversion and Edgar is a great character, so I have little doubt I shall end up reading the projected four more titles...

Also seen at: http://www.goodreads.com/review/show/72342498